Method and means for improving the accuracy of firearms by reducing barrel vibrations



Sept. 12, 1967 K. H. RECKER 3,340,641

METHOD AND MEANS FOR IMPROVING THE ACCURACY OF FIREARMS BY REDUCING BARREL VIBRATIONS 1964 2 Sh sets-Shet 1 Filed Dec. 15,

INVENTOR KENNETH H RECKER Sept. 12 1967 K H RECKER 3,340,641

PROVING T METH AND MEANS 1 01f HE ACCURACY OF EARMS BY REDU G BARREL VIBRATIONS Filed Dec. 15, 1964 2 Sheets-Sheet 2 DWI/WW INVENTOR KENNETH H. RECKER ATTORNEY United States Patent Ofltice 3,34%,641 Patented Sept. 12, 1967 METHOD AND MEANS FOR IMPROVING THE ACCURACY OF FIREARMS BY REDUCING BARREL VIBRATIONS Kenneth H. Recker, Melbourne, Fla., assignor to Heli- Pic, Inc., a corporation of Florida Filed Dec. 15, 1964, Ser. No. 418,486 12 Claims. (Cl. 42-1) The present invention relates to a method and means for improving accuracy in the shooting of firearms.

The object of the invention is to eliminate, or reduce to an infinitesimal minimum, vibrations which occur at the muzzle end of the barrel of firearms due to the explosion of the ammunition, and thereby improve the accuracy of the firearms.

Another object is to accomplish the first object with a very simple and inexpensive means of novel construction, which may be adjusted to meet and/or compensate for varying conditions which cause the vibration of the barrel of firearms, during the firing thereof.

Ever since the advent of the rifling of gun barrels, it has been a major problem to obtain and maintain the best accuracy possible in the shooting thereof, particularly of, so-called, small arms, such as rifles and the like. While manufacturers of guns exercise extreme care to design and produce uniform barrels, actions (or receivers), trigger mechanisms, stocks, etc.all in an attempt to obtain the finest accuracy possible-there remains, to those versed in the art of marksmanship, the unexplained phenomenon of why one rifle will shoot very accurately while ten or more identical weapons will not perform in a satisfactory and stable manner, although everything is equal constructionally and mechanically. So, the problem of controlling the accuracy of gunfire has been a long and arduous quest.

Attempts have been made in fitting or bedding a rifle barrel in or to the forestock in various ways and in using an adjustable tension on the barrel for controlling the barrel vibrations. At the very best, these attempts to improve their accuracy in shooting are, and have been, very unsatisfactory; and the quest continued, It is known that different batches or lots of ammunition, of the same type and caliber, vary due to variations in the explosive charge itself as well as in other characteristics, and that the individual shooting characteristics of a gun or rifle are, or may be, affected by the ambient conditions to which it is exposedall of which aifect the'vibration of the gun barrel and its shooting accuracy. This problem has not been solved heretofore in any manner that may be said to be constant or satisfactory.

Hence, the problem and its solution have continued for many years; and the importance of this problem will be appreciated, when it is remembered, that, with a 30- inch barrel, a vibration at the muzzle of 20-thousandths of an inch produces a spread over two (2) inches on the target at a distance of 100 yards. The vibration of the muzzle of many guns is much more than ZO-thousandths of an inch.

I have noW found that, by transferring the vibrations, caused by the firing of a rifle, to another piece of vibratory material, which is firmly and rigidly attached to the :gun

barrel and otherwise' free to vibrate, and controllably tuning said vibratory piece so that its natural vibrating frequency is equal to or in phase with the frequency of the vibrations of the gun barrel, during firing, the vibrations of the gun barrel are damped, absorbed or faded-out, thus improving the accuracy of the gun and obtaining closer grouping of repeated and successive shots on a target far beyond all experience hitherto realized.

My discovery, therefore, is a method of damping vibrations in a gun-barrel assembly comprising fixing a vibration absorber to said gun-barrel assembly and tuning the vibration absorber so that the natural frequency of said absorber is equal to the frequency of the vibrations of said gun barrel, during firing.

The vibration absorber should be capable of independent vibratory action and contain tuning means sufiicrent to bring the natural frequency of the absorber to equal the frequency of the vibrations of the gun barrel during firing.

The various vibration characteristics of individual rifles, as well as those caused by variances in different batches of ammunition or by ambient conditions, are compensated by manually tuning the aforesaid vibration absorber to have its vibrating frequency equal that of the gun said Weight to the point of attachment of the tuning assembly .to the barrel of the gun, during a few test target shots, until a point is reached where the test shots Show the muzzle vibrations have been eliminated.

As examples of the proportionment of the tuning bar and its weight-mass relative to the barrels of rifles, I have found that I obtain excellent results in eliminating muzzle v brations during the firing of the rifles of .22 caliber r1mfiresuch as Remington Model 37, Winchester Model 52 and Anchutz Model 54, having 28-inch barrels and of approximately l-inch diameter-when the tuning bar of this invention is 5 inches long, of an inch in diameter, about 5 ounces in weight, and secured firmly to the barrel about 7 inches forwardly of its action or receiver and with its distal or free end carrying a tuning-weight member of about 2 ounces that is adjustable along said distal end of said bar. I have also found that the closer the point of attachment or securement of the tuning bar is to the receiver of the gun, the shorter the tuning bar needs to be (probably because of smaller arc of the vibrations nearer to the receiver) and the closer the tuning bar is secured toward the muzzle of the barrel, the longer the tuning bar should be (probably because of the larger arc of the vibrations).

In selecting a vibration absorber of this invention for different makes, models and calibers of guns, one must select such a vibratory absorber of a length and weight mass having a normal frequency of vibration that Will equal the frequency of vibration of the gun barrel, during firing, while having regard of course as to the point at which the vibratory absorber is secured to the barrel.

The above described method of improving the shooting accuracy of guns may be accomplished with the devices illustrated in the accompanying drawings, in which like characters of reference refer to the same and like parts through its several views and in which:

FIGURE 1 is a side elevation view of a rifle equipped with a tuning assembly in accordance with this invention and with parts of the stock broken away in order to illustrate the constructional organization;

FIGURE 2 is an enlarged longitudinal sectional view through a fragmentary portion of the rifle barrel to which the vibration absorber is attached;

FIGURE 3 is a transverse sectional view taken sub stantially on line 3-3 of FIGURE 1;

FIGURE 4 is a transverse sectional view taken substantially on line 4-4 of FIGURE 1;

FIGURE 5 is a transverse sectional view taken substantially on line 55 of FIGURE 1;

FIGURE 6 is a longitudinal sectional view through a modified form of an adjustable weight for tuning the vibration absorber;

FIGURE 7 is a fragmentary longitudinal sectional view similar to FIGURE 2 but illustrating another manner of attaching the vibration absorber to the gun barrel and a different type of adjustable tuning weight;

Figure 8 is a longitudinal sectional view of the tuning weight shown in FIGURE 7;

FIGURE 9 is a fragmentary longitudinal sectional view similar to FIGURE 2 but illustrating another modified form of the vibration absorber;

FIGURES 10 and 11 are transverse sectional views taken substantially on line 1010 and on line 1111, respectively, of FIGURE 9;

FIGURE 12 is a fragmentary longitudinal sectional view similar to FIGURE 2 but illustrating a further modified form of the tuning assembly; and

FIGURE 13 is a transverse sectional view taken on line 1313 of FIGURE 12.

The gun or rifle 20, shown in FIGURE 1, is intended to illustrate a rifle of generally conventional construction having a stock 21 formed with the usual forestock 22 for cradling or embedding a gun-receiver or action 23 and a barrel '24, the barrel being secured to the receiver by screw threads 25 and the receiver being cradled within and secured to the rear portion of the forestock by holddown screws 27 and 28 and having a trigger mechanism 26 depending therefrom-all in the customary manner.

However, in accordance with this invention, the barrel 24 is unconfined so that any tendency of it to vibrate, during firing, is unrestricted; and, for this purpose, the barrel is not bedded in or attached to the forestock 22, the forestock being channeled deeply in its upper-side portions underlying the barrel, as at 29, so that the walls of the channel 29 will be out of cont-act with the barrel for a substantial distance and will accommodate the vibration absorber 30, which is attached to the underside of the barrel, and will permit unrestricted vibration of said absorber.

While the vibration absorber 30 may be positioned at any place along the barrel 24, it is preferred to place it at the underside of the barrel, extending in the general direction of the barrel, and within the forestock 22 for protective purposes instead of having it as a lateral projection exterior of the overall outline of the gun. It is also preferred to attach the vibration absorber assembly 30 about 7 inches from the receiver 23 or at a point about one-fourth A) of the length of the barrel from the receiver by means of a spacing lug 30a, which forms part of the vibration absorber 30 and is attached to the barrel by welding 31 or may be formed as an integral part of the barrel, or, in some instances, may be a laterally extended end of the vibration absorber which is welded to the barrel. In any event, the lug 30a spaces the absorber from the barrel to permit unrestricted vibration of the absorber.

The vibration-absorber 30, shown in FIGURES 1 to 5, inclusive, comprises, in addition to the lug 30a, a vibratory bar 30b, which is threaded along its length (or at least for a substantial distance at its opposite end portions) and has one end threadedly received in a complementally threaded bore 300 of the lug 30a. It is preferred to have the vibratory bar extend forward from the lug 30a toward the muzzle of the gun in order that the same may be more conveniently adjusted from the forward end of the forestock, as will be presently explained. The lug 304: has, preferably, an insert 30d therein of rubber, nylon or other such material surrounding a portion of its bore 30b, as will embrace or grip the end of the tuning bar, which is threaded into the bore of the lug, in order to afford sufficient friction as will hold the tuning bar 30b in its adjusted positions in the lug against the vibration or other non-deliberate forces which may tend to move it from such adjusted position. The other or distal end of the absorbing bar 30b carries an annular tuning weight 30w surrounding and slidable along the distal end portion and held in adjusted position thereon by clamps, or jam nuts 30m one at each end of the weight member.

The extremity of the distal end of the vibration absorber bar 30b is formed with a means by which the bar may be adjusted in the lug 30a to increase or decrease the amplitude of vibration of the absorber bar 30b. In FIGURE 2, this means comprises a transverse slot 30s to receive the bit-end of a screwdriver 32, which may be inserted through an opening 29a in the foreward end of the forestock 22 and communicating with the channel 29. The underside of this forestock 22 is provided with an enlarged opening 22a underlying the vibration absorber 30 so as to permit access to the Weight member 30w and the jam-nuts 3011 for purposes of adjustment by means of a jaw wrench. A cap plate 33 is provided to removably close the opening 220.

In the use of the gun shown in FIGURES 1 to 5, inclusive, the end of the vibratory bar 30b, which is connected with the lug 30a, extends through the bore 300 of the lug for a sufiicient distance as will allow such micro-adjustment thereof in either direction of its length. Then, the binding nuts 30m are adjusted to position the weight member 30w at a point on the distal end of the absorber bar where the vibrations of the vibration absorber equals the magnitude of those of the barrel, during firing. This tuning of the absorber 30 is accomplished by firing several rounds at a target to determine the grouping obtained and making the adjustments accordingly, after each firing, until zero, or approximately zero, vibrations are attained at the muzzle of the gun. However, such initial setting of the bar 30b and of the weight 30w may be done by the manufacturer. Thereafter, any further adjustment of the vibration absorber, that may be required to increase or decrease the amplitude of vibrations of said absorber to bring it into phase with vibrations of the barrel, during firing of the gun, is accomplished by microadjustment of the threaded bar 30b relative to the lug 3011 by means of the screwdriver 32.

FIGURE 6 shows an adjustable tuning weight member 50 which may be substituted for the weight 30w, shown in FIGURES 1 and 2, in order to provide heavier weight of the same size or of a smaller size than the weights shown. The weight member 50 comprises an inner sleeve element 51 of a hard material having an inner diameter that permits it to slide on the bar 3017 with a sliding fit and having a concentric outer sleeve element 52 spaced a substantial distance from the inner sleeve; and between these sleeves is disposed an annulus of lead 53 filling the area between said sleeves and in bonding contact with the opposing surfaces of said sleeves.

FIGURES 7 and 8 show another form 30' of a vibration absorber by which the invention may be practiced and wherein the end of the bar 30b, attached to the lug 30a, is held in fixed position in the bore of said lug by one or more set-screws 34 or the lug may be a lateral extension of the bar 30b welded to the barrel 24. Also in this form of the invention, the annular weight member 30w has its internal bore threaded, as at 35, to threadedly receive and be micro-adjustable on the threaded bar 30b. This weight member 30w is of the self-locking nut type having a nylon insert 301 (similarly as shown at 30d in FIGURE 2) to grip and hold the weight member in position on the bar, except against a deliberate movement imparted to it by a socket wrench 36. The Wrench 36 is insertable through the opening 29a of the forestock and engageable with a polygonal-faced projection 37 formed on one end of the weight member.

In the use of the device shown in FIGURES 7 and 8, the tuning weight member 30w is initially adjusted, either at the factory or by the user, in the manner indicated above; and, thereafter, further adjustments, as may be required to tune the assembly 30' in phase with the magnitude of the vibrations of the barrel, are accomplished by use of the tool 36.

FIGURES 9, 10 and 11 illustrate another form 30 of vibration absorber by which the invention may be practiced, and wherein the threaded bar 3012 is fixed at one end, in any suitable manner, to the spacing lug 30a rigidly attached to the gun barrel 24. The bar 3011 may not be threaded for its entirelength, but only for a substantial distance at its distal end portion. The weight member 30w has a bore therethrough, through which extends the distal end portion of the bar 30b and is slidable thereon,'

and the weight member 30w is held in adjusted positions on the bar 30b by a compression spring 38 interposed between it and the spacer lug 30a and which presses the weight member firmly against an adjusting nut 39 (preferably of the self-locking type). A washer 40 may be interposed between the nut 39 and the weight member 30w, with serrations 41 on the opposing face of the washer weight member. Also, as an added safety measure for assuring non-movement of the weight member from adjusted position, during firing of the gun, a set-screw 42 may be provided in the weight member 30w to engage in and bind against the bottom of a groove 43 provided in and along the underside of the bar 301).

In use, the vibration absorber 30 is the same as described in connection with FIGURES 7 and 8.

Another form of the vibration absorber is shown in FIGURES 12 and 13. In this assembly 30", the bar 30b may be aflixed to the spacer lug 3011 as shown in either FIGURE 7 or 9, or in any suitable manner so as to be rigid therewith, or the lug 30a may be a lateral extension of the bar 30b. The difference is that the weight member 30w may be built-up by increments of washer-like elements 44 to attain the necessary or desired weight mass of the weight member 30w by adding or removing said elements for certain types of guns in order to obtain the result sought. The elements 44 are slipped over the distal end of the tuning bar 30b and arranged in contiguous side-by-side relation and clamped together between the jam nuts 30n, as is the weight member 30w in FIGURES 1 and 2. In use, the weight member 30w of the tuning assembly 30", is adjusted initially at the factory or by the user as described in connection with FIGURE 1, and, thereafter the tuning is made by the user of the gun by adjusting the position of the composite washer-like members along the length of the tuning bar 30b and/or adding or removing washer element 44 as required by manipulation of the jam nuts 3012 with a jaw wrench inserted in the opening 22a.

From the foregoing description it will be manifest that the objects of this invention have been attained.

Having thus described the invention and the manner in which it is to be performed, it is to be understood that certain changes and variations may be made in the exact details of devices shown herein for carrying this invention into practice; and that all changes and modifications as fall within the scope of the appended claims are contemplated as part of this invention.

That which is claimed to be new and to be secured by Letters Patent is:

1. A method of improving the accuracy of guns, during the firing thereof, including the steps of transferring the vibrations of the gun barrel to a freely vibratory member by rigidly attaching a portion of said member to the barrel, and then tuning said member in phase with the magnitude of the vibration of the gun barrel, resulting from the firing of the gun.

2. In a method of improving the accuracy of guns, during the firing thereof, by controllably damping the vibrations of the barrel of the gun, said method including the steps of transferring the vibration of the gun barrel to an elongated vibratory member having one end rigidly attached to the barrel, and tuning the amplitude of said member so as to be in phase with the magnitude of the vibration of the gun barrel resulting from the firing of the gun.

3. In a method as set forth in claim 2, wherein the tuning of the vibratory member includes the shifting of a weight mass along the distal end portion of said member to an adjusted position where the amplitude of the vibratory member is in phase with the magnitude of vibrations of the gun barrel which result from firing the gun.

4. In a gun, a vibratory bar having one end portion rigidly attached to the barrel and otherwise free to vibrate, said bar being dimensioned and of a weight mass that will be vibrationally responsive to the vibrations of the barrel during firing of the gun, and means for tuning said bar to bring its amplitude of vibration into phase with the magnitude of vibrations of the barrel, whereby the vibrations of the barrel during firing are transferred and absorbed by the vibratory bar.

5. A gun having a barrel free to vibrate, during firing thereof, a vibration absorber bar having one end portion rigidly attached to the barrel and vibrationally responsive to said vibrations of the barrel, and means for adjusting the weight mass of said absorber relative to its point of attachment to the barrel to bring its amplitude of vibration in phase with the magnitude of vibration of the barrel.

6. A gun having a barrel free to vibrate during firing thereof, a vibratory bar having one end rigidly attached to the barrel and being otherwise related to the barrel to vibrate freely and responsive to the vibrations of the barrel during firing; and a weight mass adjustably mounted on the distal end portion of said bar for tuning said bar in phase with the magnitude of the vibrations of the barrel, during firing, whereby the vibrations of the barrel are damped to zero, or approximately so.

7. A gun as set forth in claim 6 wherein the weight mass comprises a plurality of separatable contiguously arranged washer like members individually insertable on and removable from the absorber bar and adjustable as a unit along said bar between two jam nuts threaded on said bar.

8. A gun as set forth in claim 6 wherein the adjustable weight mass may be employed for general tuning of said absorber bar and wherein the attachment of the absorber bar to the barrel includes a laterally projecting lug rigidly attached to said barrel and having a bore therethrough in which an end of said tuning bar adjustably extends, whereby fine tuning of the absorber bar may be effected, and means for holding the absorber bar in its adjusted positions.

9. A gun as set forth in claim 6, wherein the absorber bar is fixedly and rigidly attached to the barrel, and wherein said weight mass is threaded adjustably along the distal end portion of said absorber.

10. In a gun having an unbedded barrel free to vibrate during firing, a vibration absorber including an elongated bar extending in the same general direction of the barrel and having one end rigidly secured to the barrel, the said absorber being otherwise spaced from the barrel and unrestricted to free vibration, a tuning weight mass positioned on and adjustable along the distal end of said bar, the length of said bar and the weight of said tuning mass being so related to the barrel that the vibrations of the barrel are transferred to the bar, during firing, and absorbed thereby, when the vibration absorber has been tuned so that its vibratory frequency is in phase with the vibratory frequency of the gun barrel, during firing, resulting in elimination of vibrations at the muzzle of the barrel, during firing.

11. A gun having a barrel free to vibrate during firing thereof, a vibrator bar having one end rigidly attached to the barrel by a lug and being otherwise related to the barrel to vibrate freely and responsive to the vibrations of the barrel during firing, a nut threaded on said vibratory bar, a weight mass slidable along said bar intermediate said lug and nut, and a compression spring interposed between said lug and weight mass to maintain said weight mass in contact with said nut.

12. In a gun having a barrel supported for vibratory movement, an elongated member rigidly attached to said barrel and spaced therefrom for vibrating in accordance 7 8 With vibrations of said barrel, and means for adjustably 2,302,699 11/1942 Kilpsch 4276 X varying the natural vibration period of said member. 2,372,568 3/ 1945 Grigg 42-75.1 2,845,737 8/1958 Hoyer 42-1 References Cited 2,921,396 1/1960 Larson 42-1 UNITED STATES PATENTS 5 2,140,945 12/1938 Swartz 42 1 BENJAMIN A. BORCI-IELT, Przmar y Exammer. 

4. IN A GUN, A VIBRATORY BAR HAVING ONE END PORTION RIGIDLY ATTACHED TO THE BARREL AND OTHERWISE FREE TO VIBRATE, SAID BAR BEING DIMENSIONED AND OF A WEIGHT MASS THAT WILL BE VIBRATIONALLY RESPONSIVE TO THE VIBRATIONS OF THE BARREL DURING FIRING OF THE GUN, AND MEANS FOR TUNING SAID BAR TO BRING ITS AMPLITUDE OF VIBRATION INTO PHASE WITH THE MAGNITUDE OF VIBRATIONS OF THE BARREL, WHEREBY THE VIBRATIONS OF THE BARREL DURING FIRING ARE TRANSFERRED AND ABSORBED BY THE VIBRATORY BAR. 